Yes, I am afraid when Gollancz reprinted The Heart of Fire, they opted to go with black and white maps rather than colour (to save money!).
The original colour section is available on the downloads page:
Your only other option is to try and get one of first edition printings (so that will the the large format version of Heart of Fire, which will match the size of your Legion of Shadow. Not sure how you would hunt one of those down (there is one on Amazon Uk for £175!). Maybe keep checking eBay?
The other books all have colour maps (Winter's Fury and Raiders of Dune Sea).